300 PRC Versus 300 Winchester Magnum — Ron Spomer Outdoors

First, understand that Hornady did not create the 300 Precision Rifle Cartridge to leave the 300 Winchester Magnum in its slip stream. They did not seek to out run the King, let alone faster 30s like 300 RUM and 30-378 Wby. Mag.

What Hornady aimed at was performance characteristics the U.S. Special Operations Command had identified: increased first-round hits on humanoid targets at extreme ranges. Fifteen hundred yards. Even 2,000 yards.

Well shucks, with the right bullet the 300 Win. Mag. can reach that far. So can all faster 300s. So if the PRC didn’t beat their velocities, how could it outperform them?

By being more accurate. Consistently. Across all rifle platforms. And that meant minimizing wind deflection, among other things…

Genesis of the 300 PRC

To reach this precision shot placement objective, Hornady knew its new 30-caliber of 2018 needed to throw bullets with high Ballistic Coefficient ratings. That meant long, sleek, heavy boat tails with secant ogive nose profiles. Stabilizing such long bullets would require rifling twist faster than the 1:10” standard for the 300 Win. Mag. Hornady made it 1:8.5”, quick enough to stabilize streamlined .308 bullets as long as 1.858”, the length of Hornady’s 250-grain A-Tip Match bullet.

To propel such bullets, Hornady grabbed the 375 Ruger case, shortened it a smidge under 300 Win. Mag. length, and gave it today’s popular 30-degree shoulder. The most obvious benefit of the 375 RCM case was what it didn’t have. A belt. The case rim and head diameter are the same .532” as the 300 Win. Mag., but instead of stepping body size down to .513” to create the headspacing belt, body diameter remains .532” before tapering to .515” at the shoulder. This creates sufficient powder space to more than compensate for the slightly shorter base-to-shoulder length of the case. A 300 PRC case should hold about five percent more powder than a 300 Winchester Magnum case. That results in a seemingly negligible 25- to 50-fps muzzle velocity advantage, but as we’ll see, negligible becomes appreciable at the extended ranges where the 300 PRC is designed to work.